Meanwhile, there was a wide variety of research going on at the General Electric Laboratory, from basic investigations to the development of new electric consumer goods such as blankets and toasters. Coolidge played his part.
Since Roentgen's discovery of X-rays in 1895, the use of X-rays as a diagnostic tool had intrigued the medical community. Coolidge had studied X-rays while in college and met Roentgen in Leipzig; his interest in X-rays persisted.
In his X-ray tube, Coolidge improved on existing models by substituting tungsten as the material in both the heated filament and the target anode and by completely removing ionizing gases from the tubes atmosphere. The result was a consistent and guidable X-ray generator for medical diagnosis and treatment. Further improvements to the 1913 original increased the power of the radiation leading to the non-destructive analytical methods of X-ray crystallography.